1. Field of the Invention
The present invention relates to a wireless IC device, and, more particularly, to a wireless IC device having a wireless IC chip used in an RFID (Radio Frequency Identification) system, an electronic apparatus including the wireless IC device, and a method for adjusting a resonant frequency of a wireless IC device.
2. Description of the Related Art
In recent years, an RFID system has been developed as an article management system, which includes: a reader/writer that generates an induction field; and an IC chip (also referred to as IC tag or wireless IC chip) that has stored predetermined information therein and is attached to an article, a container, or the like, and noncontact communication is established between the reader/writer and the IC chip to transmit the information therebetween.
Japanese Unexamined Patent Application Publication (Translation of PCT Application) No. 11-515094 discloses an RFID tag including an IC chip and an antenna formed within a printed wiring circuit board. In the RFID tag, the antenna within the printed wiring circuit board and the IC chip mounted on the principal surface of the board are connected to each other in an electrically conductive state. Miniaturization of the RFID tag is achieved by disposing the antenna within the printed wiring circuit board.
However, because the RFID tag includes a dedicated antenna, a process of fabricating an antenna is required, leading to an increase in cost. Further, a mounting space for the antenna is also required, resulting in an increase in size. If the IC chip is changed, it is necessary to change the shape of the antenna or the like as well.